The Development of Quinoxaline-Based Electron Acceptors for High Performance Organic Solar Cells.

In the recent advances of organic solar cells (OSCs), quinoxaline (Qx)-based non-fullerene acceptors (QxNFAs) have attracted lots of attention and enabled the recorded power conversion efficiency (PCE) approaching 20%. As an excellent electron-withdrawing unit, Qx possesses advantages of many modifiable sites, wide absorption range, low reorganization energy and so on. To develop promising QxNFAs to further enhance the photovoltaic performance of OSCs, it is necessary to systematically summarize the QxNFAs reported so far. In this review, all the focused QxNFAs are classified into five categories as following: SM-Qx, YQx, fused-YQx, giant-YQx, and polymer-Qx according to the molecular skeletons. The molecular design concepts, relationships between the molecular structure and optoelectronic properties, intrinsic mechanisms of device performance are discussed in detail. At the end, we sum up the advantages of this kind of materials, prospect the molecular develop direction, give the challenges faced by QxNFAs and advise constructive solutions to the existing problems. Overall, this review presents unique viewpoints to conquer the challenge of QxNFAs and thus boost OSCs development further toward commercial applications. This article is protected by copyright. All rights reserved.